Intersections in 3d model
Blender 2.81 adds support for the Voxel Remesh operator, which can efficiently get rid of intersecting geometry such as meshes generated by tightly turning or self-intersecting beveled curves, for example this one:

The step by step process goes like this:

Ensure that the endpoints are capped - you can manually add faces later but since you are using a profile curve anyway, it's easy to add caps right here:



Convert the curve to mesh: Object -&gt; Convert to -&gt; Mesh From Curve/Surf/Meta/Text.

Press F3 (operator search) -&gt; type &quot;Voxel Remesh&quot;



The result should now be something like this. Note that there are visible &quot;welds&quot; because the voxel resolution is not too big.

To adjust the parameters for the voxels, select the mesh, enter sculpt mode,

Then on the properties window adjust the settings for the remesh operation.